Method For Controlling A Machine

ABSTRACT

The present disclosure is related to a method of controlling a machine having an engine, a hydraulic pump and an operator input device. The method includes storing operation data corresponding to multiple operating parameters of the machine over a predetermined number of working cycles. The operation data is compared with respective predetermined ranges of operating parameters. Further, the machine in controlled in a normal mode of operation if the stored operation data lies outside the respective predetermined ranges. Further, the machine is controlled in an override mode if the stored operation data lies within the predetermined ranges. In the override mode, the machine is controlled based on estimated values of the operating parameters. Further, the method includes switching to the normal mode if a current operator input lies outside a predetermined range of the operator input.

TECHNICAL FIELD

The present disclosure relates to a method for controlling a machine having an engine.

BACKGROUND

Machines such as, a hydraulic excavator, generally perform repetitive working cycles during various operations, such as trenching, levelling, and the like. During execution of such working cycles, a sudden high power demand may be placed on an engine of the machine by an operator. Such a sudden power demand may decrease a speed of the engine, causing the operator to move the operator lever to increase the power output from the engine. More often the operator might be moving the operator lever more than the required power demand, thus leading to increased fuel consumption and loss in fuel efficiency of the machine.

For reference, U.S. Pat. No. 7,588,118 (the '118 patent) discloses a work machine with an engine control device which is capable of ensuring fine controllability. To this end, the work machine includes: an engine control device for controlling the output of an engine in accordance with each of a plurality of operation modes which are set according to the contents of operations; and operation mode selector switches for selecting any one of the plurality of operation modes. If the operation mode selector switches select, from the plurality of operation modes, an operation mode for setting a set revolution speed for the engine to a relatively low value, the engine control device performs isochronous control for maintaining the revolution speed of the engine to a constant value irrespective of load fluctuations. However, isochronous control, as disclosed by the '118 patent, may not be able to change the revolution speed of the engine in case of sudden request for high engine power by an operator of the work machine.

SUMMARY OF THE DISCLOSURE

In one aspect of the present disclosure, a method of controlling a machine is provided. The machine includes an engine, a hydraulic pump drivably coupled to the engine, and an operator input device configured to receive an operator input. The method includes determining a plurality of operating parameters of the machine. The plurality of operating parameters includes at least a speed of the engine, a pressure of the hydraulic pump, and the operator input. The method further includes storing operation data over predetermined number of working cycles of the machine. The operation data corresponds to each of the operating parameters of the machine. The method also includes comparing the stored operation data corresponding to each of the operating parameters with respective predetermined ranges of the operating parameters. The method includes controlling the machine in a normal mode of operation if the stored operation data lies outside the respective predetermined ranges. In the normal mode of operation, the engine and the hydraulic pump are controlled based on the operator input. The method further includes estimating values of the operating parameters based on the stored operation data if the stored operation data lies within the respective predetermined ranges.

The method includes switching to an override mode of operation of the machine. In the override mode, the engine and the hydraulic pump are controlled based on the estimated values of the operating parameters. The method includes comparing a current operator input with a predetermined range of the operator input. The method includes continuing to control the machine in the override mode if the current operator input lies within the predetermined range. The method further includes switching to a normal mode of operation of the machine if the current operator input lies outside the predetermined range.

Other features and aspects of this disclosure will be apparent from the following description and the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a side view of an exemplary machine;

FIG. 2 illustrates a block diagram of a control system of the machine, according to an embodiment of the present disclosure;

FIG. 3 illustrates a flow diagram for controlling the machine, according to an embodiment of the present disclosure; and

FIG. 4 illustrates a method of controlling the machine, according to an embodiment of the present disclosure.

DETAILED DESCRIPTION

Reference will now be made in detail to specific embodiments or features, examples of which are illustrated in the accompanying drawings. Wherever possible, corresponding or similar reference numbers will be used throughout the drawings to refer to the same or corresponding parts.

FIG. 1 shows an exemplary machine 100. In the illustrated embodiment, the machine 100 is a hydraulic excavator. Alternatively, the machine 100 may be any machine including, but not limited to, a wheel loader, a shovel, a backhoe loader, a dozer, a wheel excavator, and the like. Further, the disclosure may be applied to different types of machines used in industries including, but not limited to, earth-moving, construction, transportation, agriculture, forestry, and waste management.

Referring to FIG. 1, the machine 100 includes a main frame 102. The machine 100 further includes an implement assembly 104 coupled to the main frame 102. The implement assembly 104 includes a boom member 106, an arm member 108 pivotally coupled to the boom member 106 and an implement member 110 pivotally coupled to the arm member 108. In the illustrated embodiment, the implement member 110 is a bucket. In an alternate embodiment the implement member 110 may be a drilling tool, a grapple and the like. The implement assembly 104 further includes multiple implement actuation members for actuating the implement member 110. In the illustrated embodiment, the implement actuation members include a boom cylinder 112, an arm cylinder 114 and an implement cylinder 116. The boom cylinder 112 is configured to move the boom member 106 relative to the main frame 102. Further, the arm cylinder 114 is configured to move the arm member 108 relative to the boom member 106. Moreover, the implement cylinder 116 is configured to move the implement member 110 relative to the arm member 108. Hence, the various cylinders 112, 114, 116 may be regulated to control the movement of the implement member 110.

The main frame 102 is further mounted on an undercarriage assembly 118. The undercarriage assembly 118 is configured to rotatably support the main frame 102, and provide propulsion and steering to the machine 100 via ground engaging members 120. As shown in FIG. 1, the main frame 102 may be rotatable about an axis A-A′ with respect to the undercarriage assembly 118. In the illustrated embodiment, the ground engaging members 120 includes one or more continuous track assemblies having multiple track links and track shoes. In an alternative embodiment, the ground engaging members 120 may include one or more continuous rubber tracks, wheels and the like.

The machine 100 further includes an operator cabin 122 provided in the main frame 102. The operator cabin 122 may include an operator seat (not shown) and multiple control devices configured to control the machine 100 for various operations.

The machine 100 further includes a power source such as an engine 208 (shown in FIG. 2). The engine 208 may be an internal combustion engine which runs on diesel, gasoline, gaseous fuels, or a combination thereof. The engine 208 may be of various configurations, such as in-line, V-type etc. Further, the engine 208 may provide power to various components of the machine 100 such as the ground engaging members 120 and the implement assembly 104.

FIG. 2. illustrates a block diagram for a control system 200 of the machine 100, according to an embodiment of the present disclosure. The controls system 200 may include an operator input device 204 which is configured to receive an operator input. The operator input device 204 may include one or more of an operator lever, a joystick, a pedal, a switch and the like. Further, the control system 200 may also include a display (not shown) for displaying various parameters associated with the machine 100.

Further, the operator input device 204 is communicably coupled to a control unit 206. The control unit 206 may also be configured to receive signals from one or more sensors of the machine 100. The control unit 206 may be configured to receive the operator input from the operator input device 204 and regulate various components of the machine 100. Additionally, the control unit 206 may also perform various control operations based on predetermined control strategies stored in a memory associated with the control unit 206. The control unit 206 may be embodied as a microcontroller, a computer, and the like. The control unit 206 may further be configured to regulate the engine 208, a hydraulic pump 210 and a valve unit 212. In an embodiment, the control unit 206 may regulate the engine 208 by controlling the supply of fuel. Further, the engine 208 is drivably coupled to the hydraulic pump 210 by an output shaft (not shown). In various embodiments, the hydraulic pump 210 may be a variable displacement pump, or a variable speed pump. The control unit 206 may control the hydraulic pump 210 in order to regulate a flow and/or pressure of a hydraulic fluid supplied by the hydraulic pump 210. The hydraulic fluid discharged from the hydraulic pump 210 may be supplied to the valve unit 212. In an embodiment, the valve unit 212 may include one or more proportional valves, check valves, pressure regulator valves, and the like. The valve unit 212 may be regulated by the control unit 206 to selectively supply the hydraulic fluid to the boom cylinder 112, the arm cylinder 114 and the implement cylinder 116. The valve unit 212 may also regulate a flow of the hydraulic fluid from the cylinders 112, 114, 116 to a tank. The control unit 206 may therefore control the movement of the implement member 110 by regulating the flow of the hydraulic fluid to and from the cylinders 112, 114 and 116 via the valve unit 212.

It may be contemplated in addition to the hydraulic pump 210, that the engine 208 may also drive other components of the machine 100, such as the ground engaging members 120 and an alternator. Further, the hydraulic pump 210 may also supply the hydraulic fluid to other actuators of the machine 100, such as a swing motor (not shown) configured to move the operator cabin 122 with respect to the undercarriage assembly 118.

Typically, the machine 100 may perform various operations, such as trenching, levelling or pipe laying. During a trenching operation, the control unit 206 may regulate the engine 208, the hydraulic pump 210 and the valve unit 212 in order to repetitively execute a trenching cycle which includes a digging segment, a first swing segment, a dump segment and a second swing segment. During the digging segment, material may be excavated from ground by manipulating the implement member 110. During the first swing segment, the main frame 102 may rotate with respect to the undercarriage assembly 118 to a dumping location. During the dump segment, the excavated material may be dumped by manipulating the implement member 110. During the second swing segment, the main frame 102 may rotate back to a digging location. Subsequently, the trenching cycle may be repeated. Similarly, a levelling operation and a pipe laying operation may include multiple cycles with each cycle having one or more segments. The details of the trenching cycle, as described above, is for illustrative purposes only, and the trenching cycle may include any additional segments within the scope of the present disclosure. Further, the machine 100 may also be configured to perform various other working cycles in addition to the trenching cycle.

FIG. 3 illustrates a flow diagram 300 for controlling the machine 100, according to an embodiment of the present disclosure. In an embodiment, various steps in the flow chart 300 may be executed upon activation of the engine 208. Additionally or optionally, the steps of the flow diagram 300 may be executed upon detection of a specific operation of the machine 100 based on the operator input.

At step 302, a plurality of operating parameters of the machine 100 are determined. The control unit 206 may determine the operating parameters, such as a speed of the engine 208, the pressure of the hydraulic pump 210, and the operator input from the operator input device 204. The pressure of the hydraulic pump 210 may be the pressure of the hydraulic fluid supplied by the hydraulic pump 210. The operating parameters for the operator input may include angular velocity and angular displacement of the operator lever (not shown). At step 304, the control unit 206 may store the operating data corresponding to each of the operating parameters within the memory associated with the control unit 206, for a predetermined number of working cycles. In an example, during a trenching operation, the control unit 206 may store the operation data for three trenching cycles. In an embodiment, the operating data may be stored at predefined time intervals.

At step 306, the stored operation data corresponding to each of the operating parameters is compared with a predetermined range of the operating parameters via the control unit 206. Further, the control unit 206 may determine if the stored operating data corresponding to each of the operating parameters is within predetermined ranges of the operating parameters. In an example, the control unit 206 may determine that the stored data corresponding to the speed of the engine 208 for the predetermined number of cycles lie within the predetermined range of the engine speed. Similarly, the predetermined range of the operator input may correspond to a range of the angular displacement of the operator lever. The predetermined ranges may be calculated based upon simulation and test results of the machine 100. Further, the predetermined ranges may be part of a database stored in the memory associated with the control unit 206.

At step 310, the machine 100 is controlled in a normal mode of operation if the stored operation data lies outside the respective predetermined ranges. In the normal mode of operation, the engine 208, the hydraulic pump 210 and the valve unit 212 may be controlled based on the operator input from the operator input device 204.

At step 312, the control unit 206 estimates the values of the operating parameters based on the stored operation data if the stored operation data lies within the respective predetermined range. For example, the control unit 206 may estimate the values of the operator input, the speed of the engine 208 and the pressure of the hydraulic pump 210 based on the stored operation data at step 304. Further, the estimated values are stored within the memory associated with the control unit 206.

At step 314, the control unit 206 controls the machine 100 in an override mode. In the override mode, the machine 100 is controlled by the estimated values of the operating parameters of the machine 100. The control unit 206 may regulate a supply of fuel to the engine 208 and the displacement of the hydraulic pump 210 based on the estimated values. In an example, the control unit 206 may determine the displacement of the hydraulic pump 210 and the amount of fuel supplied to the engine 208 at different points of the working cycle based on the estimated values. In case the working cycle is a trenching cycle, the control unit 206 may determine the displacements of the hydraulic pump 210 and the fuel supply amounts during various points of the dig segment, the first swing segment, the dump segment and the second swing segment, and control the machine 100 accordingly.

At step 316, the control unit 206, compares a current operator input with a predetermined range. The control unit 206 may continue to receive operator input during the override mode of control of the machine 100. If the control unit 206 determines that the current operator input is within a predetermined range of the operator input, then the control unit 206 continues to operate the machine 100 in the override mode at step 314. However, if at step 316, the control unit 206 determines that the operator input lies outside the predetermined range, the control unit 206 controls the engine 208 in the normal mode at step 308.

INDUSTRIAL APPLICABILITY

The present disclosure relates to a control system 200 that is configured to implement one or more control logics of the flow diagram 300 illustrated in FIG. 3. Accordingly, the control system 200 may analyze the operating parameters for each cycle of operation and determine if the machine 100 needs to be controlled either in the normal mode or the override mode.

Referring to FIG. 4, a method 400 of controlling the machine 100 is illustrated. In an embodiment the method 400 may be implemented by various components of the control system 200, such as the operator input device 204, and the control unit 206 that regulates the engine 208, the hydraulic pump 210 and the valve unit 212. At step 402, the method 400 includes determining the plurality of operating parameters of the machine 100. The plurality of operating parameters include at least the speed of the engine 208, the pressure of the hydraulic pump 210, and the operator input from the operator input device 204. At step 404, the method 400 includes storing the operation data over the predetermined number of working cycles of the machine 100. The operation data corresponds to each of the operating parameter of the machine 100.

At step 406, the method 400 includes comparing the stored operation data corresponding to each of the operating parameters with respective predetermined ranges of the operating parameters. At step 408, the method 400 includes controlling the machine 100 in the normal mode of operation if the stored operation data lies outside the respective predetermined ranges. In the normal mode of operation, the engine 208 and the hydraulic pump 210 are controlled based on the operator input. At step 410, the method 400 includes estimating values of at least the operator input, the speed of the engine 208 and the pressure of the hydraulic pump 210 if the stored operation data lies within the respective predetermined ranges.

At step 412, the method 400 includes switching to the override mode of operation of the machine 100. In the override mode, the engine 208 and the hydraulic pump 210 are controlled based on the estimated values of the operating parameters. At step 414, the method 400 includes comparing the current operator input with the predetermined range of the operator input. At step 416, the method 400 includes continuing to control the machine 100 in the override mode if the current operator input lies within the predetermined range. At step 418, the method 400 includes switching to the normal mode of operation of the machine 100 if the current operator input lies outside the predetermined range.

In an embodiment, one or more of the steps of the method 400 may be implemented by the control system 200. With such an implementation, a decrease in speed of the engine 208 due to sudden request of high engine power by the operator may be prevented as the control system 200 and the method 400 may estimate such a high power demand beforehand, and control the engine 208 and the hydraulic pump 210 accordingly. This may further reduce a fuel consumption of the machine 100. Additionally, such an implementation may improve the control of the operator as the power is available before demand.

While aspects of the present disclosure have been particularly shown and described with reference to the embodiments above, it will be understood by those skilled in the art that various additional embodiments may be contemplated by the modification of the disclosed machines, systems and methods without departing from the spirit and scope of what is disclosed. Such embodiments should be understood to fall within the scope of the present disclosure as determined based upon the claims and any equivalents thereof. 

What is claimed is:
 1. A method of controlling a machine having an engine, a hydraulic pump drivably coupled to the engine, an operator input device configured to receive an operator input, the method comprising: determining a plurality of operating parameters of the machine, wherein the plurality of operating parameters comprise at least a speed of the engine, a pressure of the hydraulic pump, and the operator input; storing operation data over a predetermined number of working cycles of the machine, wherein the operation data corresponds to each of the operating parameters of the machine; comparing the stored operation data corresponding to each of the operating parameters with respective predetermined ranges of the operating parameters; controlling the machine in a normal mode of operation if the stored operation data lies outside the respective predetermined ranges, wherein in the normal mode of operation, the engine and the hydraulic pump are controlled based on the operator input; estimating values of at least the operator input, the speed of the engine and the pressure of the pump based on the stored operation data if the stored operation data lies within the respective predetermined ranges; switching to an override mode of operation of the machine, wherein in the override mode, the engine and the pump are controlled based on the estimated values of the operator input, the speed of the engine and the pressure of the hydraulic pump; comparing a current operator input with a predetermined range of the operator input; continuing to control the machine in the override mode if the current operator input lies within the predetermined range; and switching to a normal mode of operation of the machine if the current operator input lies outside the predetermined range. 